Difference between revisions of "83Plus:Ports:8E"
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(Port 8E: pipe number) |
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Revision as of 19:43, 11 November 2010
Synopsis
Port Number: 8Eh
Function: USB Pipe Number
This port controls which USB pipe is currently selected for I/O operations.
| This port only exists on the the TI-84 Plus and the TI-84 Plus Silver Edition. On the standard TI-83 Plus, it acts as a shadow of port 06. On the TI-83 Plus Silver Edition, this port has no effect. |
Read Values
- Always 0.
Write Values
- Pipe number (values 0 to 3 work; I'm not sure about other values.)
Comments
The USB controller supports 4 (or possibly more) separate "pipes", which can be used to perform multiple USB transactions simultaneously. Pipe 0 is always used for control transactions (endpoint zero), and behaves strangely in many ways. The other pipes can be used for bulk, interrupt, and/or isochronous transactions; they are typically mapped to endpoints 1 to 3, but do not necessarily need to be.
This port has no effect on its own; it merely determines which pipe is used by subsequent I/O operations. The following ports are affected by the currently-selected pipe:
